Metal working

ABSTRACT

A method of increasing the thickness of a zone of a thin-walled metal member of circular cross-section comprising: heating the metal in the zone to a temperature at which it can be plastically deformed, and applying axial force to the metal in the zone by a first surface which makes rolling engagement with the member and which moves relatively to the member around the circumference of the member, while also applying radial restraint by further surfaces which make rolling engagement with the member so as to locate the thickened metal relatively to the remainder of the member.

ilnited States Patent 1 Proops et al.

Assignee:

METAL WORKING Inventors: William Alfred Proops; Stuart Apsley Bridges,both of Bristol, England Secretary of State for Defence in Her BrittanicMajestys Government of the United Kingdom of Great Britain andNorthernIreland, London, England Filed: Aug. 3, 1971 Appl. N0.: 168,693

Foreign Application Priority Data Aug. 4, 1970 Great Britain 37,658/70Lohmann 72/84 June 12, 1973 515,403 2/1894 Marcy 72/356 1,744,549 1/1930Hopkins. 72/110 1,745,514 2/1930 Taylor 72/87 Primary Examiner-Lowell A.Larson AttorneyStevens, Davis, Miller & Mosher [57] ABSTRACT A method ofincreasing the thickness of a zone of a thin-walled metal member ofcircular cross-section comprising: heating the metal in the zone to atemperature at which it can be plastically deformed, and applying axialforce to the metal in the zone by a first surface which makes rollingengagement with the member and which moves relatively to the memberaround the circumference of the member, while also applying radialrestraint by further surfaces which make rolling engagement with themember so as to locate the thickened metal relatively to the remainderof the member.

5 Claims, 7 Drawing Figures METAL WORKING Gas turbine engines foraircraft include components which are fundamentally cylindrical orconical in shape, of large diameter, and with a wall which is thin inrelation to the diameter. These components are required to haveadditional metal at one or more zones. For example, flanges may berequired at the ends, to permit a component to be connected to anotherone. There may be a need to provide a pair of circumferential flanges,to define between them a groove to receive a sealing member.

The present invention concerns a method by which such components can bemade from an integral blank, without the need to remove very largequantities of metal from the blank.

According to this invention a zone of the end or edge of a thin-walledmetal member of circular cross-section in increased in thickness byheating the metal in the zone to a temperature at which it can beheating the metal in the zone to a temperature at which it can beplastically deformed, and applying axial force to the metal in the zoneby a first surface which makes rolling engagement with the member andwhich moves relatively to the member around the circumference of themember, while also applying radial restraint by further surfaces whichmake rolling engagement with the member so as to locate the thickenedmetal relatively to the remainder of the member.

The metal member may be a tubular blank which has been produced from apiece of sheet metal, rolled into a cylinder or cone, with a butt-weldedlongitudinal seam. I

The present method has many advantages, as compared with the methodusually used hitherto, namely forming the majority of the component byrolling up sheet metal, and then adding the necessary flanges, bywelding on of annular pieces which have been produced separately asforgings. The advantages include:

1. Material costs are substantially reduced. Expensive flange forgingsare replaced by a small increase in sheet metal at low cost.

2. Mechanical strength and reliability are increased by the eliminationof difficult welded joints and by improved grain flow.

3. Machining is simplified. Part-machining of forgin gs prior to weldingis eliminated, distortion is reduced and full requiring of flanges canbe carried out in unit form.

4. Indirect costs are substantially reduced. There can be reduced stockholding in raw material and partmachined stores, requireing lesshandling. Fewer jigs and fixtures are necessary. Inspection ofpart-machined components and large welded joints are eliminated.

It is known to upset ends of pipes by heating the ends and applyingpressure to them, but this procedure does illustrated by theaccompanying drawings, in which:

FIG. 1 is a perspective view of an arrangement of rollers for applyingaxial force and radial restraint;

FIG. 2'is a vertical section of the same arrangement;

FIG. 3 is a diagram showing, in cross section, successive stages indeformation of an end zone of a tubular blank;

FIG. 4 and FIG. 5 show two alternative arrangements of rollers;

FIG. 6 is a section showing two flanges on a component; and

FIG. 7 is a diagram of an apparatus for forming one of the two flangesshown in FIG. 6.

FIGS. 1 to 3 show the formation of an external flange on one end of acylindrical tubular blank 1. The machine used is an ordinary verticalboring machine with minor modifications. The blank is mounted with itsaxis vertical on the table of the machine, not shown, which can rotateabout the axis.

As shwn in FIGS. 1 and 2, the means for applying downward axial force tothe upper end of the blank is a roller 4, and the means for applyingradial restraint is two rollers 6 and 8, the operative faces 10 and 12of which are part-spherical. These rollers are on a common axis, and arecarried by a non-rotating shaft M which is mounted in a bracket 15 onthe usual tool slides 16 and 18 of the boring machine.

The roller 4 is constituted by the central part of a sleeve 20 which canturn on the shaft 14. The roller 6 is fixed to the sleeve and is locatedby a thrust bearing 22 abutting one arm 23 of the bracket 15. The roller8 can shift axially along the sleeve 20 under control of a nut 24 whichis threaded at 26 onto the shaft 14. The nut is journalled in a secondarm 27 of the bracket 15, and contains a bearing 28 for the sleeve 20.The nut abuts a thrust bearing 30 for the roller 8. The nut 24 'can beturned by a handle 32 and locked by a further nut 34.

In operation, the table of the machine is rotated, thus rotating theblank 1. The rollers are shifted horizontally on the slide 16 so as tobring the surface 10 of the roller 6 to a position tangent to the innercylindrical surface of the blank. Then the rollers are fed downwards onthe slide 18 to bring the roller 4 into engagement with the upper end ofthe blank.

The upper end'zone of the blank is heated by a multitum inductionheating element 2. This heating element is mounted on the bracket 15, bymeans not shown. As shown in FIG. 1, the heating element extends over anarc of the circumference of the blank, and the rollers occupy a positionsuch that they act on a part of the blank soon after that part has leftthe heating element. However, to facilitate understanding of thefunction of the heating element, its position in relation to the blankis indicated in chain lines at 2 in FIG. 3A as if it were notcircumferentially offset from the rollers.

For the operation of forming the flange on the blank, the bracket 15carrying the rollers and the heating element is fed gradually downwards,as indicated by the arrows 36 in FIG. 3. In addition, by turning the nut24, the roller 8 is shifted gradually radially outwards, as indicated bythe arrows 38.

The initial shape of the blank is shown in FIG. 3A. At this stage, thereis a radial clearance 40 between the outside of the blank and the roller8. The rollers are fed downwards, and when the metal has been deformedso as to fill the clearance 40, then the outward movement.

38 of the roller 8 commences. The metal is progressively deformed,passing through the situations shown in FIGS. 38 and 3C, and the finalshape of the blank is as shown in FIG. 3D. A relatively small amount ofmetal is then machined away to the outline 42, to produce the finalshape of the flange.

In the example shown, the thickness of the material of the blank is 0.2inches.

The rough dimensions of the flange in FIG. 3D are 1.0 ins. by 0.5 ins.

The axial travel of the rollers and heater is approximately 2 inches.Larger flanges may be made from the same material.

If the metal is stainless steel, the electric supply to the heatingelement is adjusted so that the metal is heated to 1120C.

For a blank measuring 12 inches diameter, a suitable rate of rotation isapproximately 11 rpm, and the rate of axial feed of the rollers andheating element is 0.050 inch per revolution. That is to say 40revolutions are necessary to carry out the process. The metal reachesoperating temperature in to 15 secs. from switching on the heater.

The invention can be applied to a wide range of sizes of metal member,from as small as about 4 ins. diameter, to as large as availablemachinery can handle. The advantages compared with upsetting become lessas the diameter decreases to 4 ins. According to the diameter of themember, it is necessary to adjust the position of the heater as seen inplan, so as to be as close to the member as is possible without risk ofshort circuiting. For small sizes, the roller 6 may be changed foranother having apart-spherical surface of smaller radius, since thisradius must be smaller than the internal radius of the member.

The roller 8 need not have a part-spherical operative face; this facecould be flat.

FIG. 4 shows an alternative arrangement of rollers, which is similar ineffect to that shown in FIG. 1, in that there are three effectivesurfaces, which engage the top of the flange, and the radially inner andouter surfaces.

Axial force is applied to the upper end of the blank by a surface 44 ofa roller 46, the axis of which is in a radial plane of the blank,inclined to the axis of the blank. Radial restraint is provided by asecond surface 48 of the roller 46, and by a surface 50 of a roller 52.The roller 52 is cylindrical and its axis is vertical, lying in the sameplane as the axis of the roller 46. The rollers 46 and 52 and theheating element 2 are all fed axially downwards at the same rate, asindicated by the arrow 54. At the same time, the roller 52 is shiftedgradually radially outwards as indicated by the arrow 56. In FIG. 4, theinclination of the axis of the roller 46 is shown as 45 to the vertical.The angle depends upon the size of the blank. The angle is chosen tofive rolling contact of the roller at all times, and thus the axis ofthe roller must pass through the inter-section of the axis of the blankand the plane of the top surface of the flange.

In FIGS. 1 and 4, the bottom surface of the flange is not positivelycontrolled. FIG. 5 shows how control may be applied if desired. In FIG.5 there are three separate cylindrical rollers 58,60,62, the axis of 58being horizontal and the axes of 60 and 62 being vertical in a planewhich is radial to the blank 1. The axis of the roller 58 is parallel tothis plane but displaced a little from it, so that the lowest part ofthe roller 58 does no foul the rollers 60 and 62.

The roller 62 has a rectangular-sectioned groove 64 in its periphery,into which metal is displaced as the three rollers are fed downwards.The roller 62 does not move away from the roller 60. That is to say, theradial restraint exerted by the roller 62 only becomes effective towardsthe end of the operation. If a flange of large radial extent isrequired, the operation may be in two stages, the roller 62 beingreplaced for the second stage by a roller having a groove which has agreater radial dimension.

FIG. 6 shows a blank which has been formed with two flanges, namely aterminal flange 65, and an intermediate flange 66, which between themdefine a groove 68 suitable for receiving a sealing element.

The flange 66 is formed first, and a suitable apparatus is shown in FIG.7. In this case it is not practical to use induction heating, andresistance heating is used instead. One electrode consists of twoconcentric cylindrical members 70 and 72. The other electrode consistsof a roller 74 with a groove 76. The groove 76 serves to accommodatemetal which will later be required to form the base of the groove 68,and to form the flange 64. In the electrode 72 there is a groove 78,into which metal is progressively deformed as a result of theapplication of axial pressure by means of the roller 74. This axialpressure procuces the intermediate flange 66. The metal of the flange isrestrained both by the bottom and outer wall of the groove 78, and alsoby the flange 80 of the roller 74.

After the intermediate flange 66 has been completed in this way, theelectrode components 70 and 72 are removed, and then the end flange 64is formed in the same way as shown in FIGS. 1 to 3.

We claim: I

1. A method of producing at one end of the wall of a thin-walled metalmember of circular cross section, a zone of greater thickness than thewall of the member, comprising the steps of:

a. locally heating successive parts of the circumference of the end ofthe member to a temperature at which they can be plastically deformed,by causing relative movement between a source of heat and thecircumference of the member,

b. deforming the metal solely by applying axial force to that part ofthe circumference of the end of the member which at any instant isheated, by means of a first surface which makes rolling engagement withthe member and moves relatively to the member around the circumferenceof the member, and

c. applying radial restraint by means of further surfaces which makerolling engagement with the member so as to locate the thickened metalrelatively to the remainder of the member, the first surface at itsinstantaneous place of contact with the member being always tangent to aplane perpendicular to the axis of the member, and the deformation ofthe metal being progressive, starting at the end of the member.

2. A method according to claim 1, including the further step ofprogressively increasing the spacing between said further surfacesduring said deforming of the metal.

3. Apparatus for producing at one end of the wall of a thin-walled metalmember of circular cross section, a zone of greater thickness than thewall of the member, comprising a support for the member and a mounting,means for relatively rotating the support and the mounting about anaxis, a first roller surface carried by the mounting and adapted toapply axial force to the member, means for relatively moving this firstroller surface towards the support, a second roller surface and a thirdroller surface both carried by the mounting and adapted to engage theinner and the outer faces of the zone respectively at a common station,means for shifting the second and third roller surfaces relatively toeach other in a direction perpendicular to the axis of relative rotationof the support and the mounting, and means on the mounting adjacent tothe first roller for locally heating the end of the wall of the member.

4. Apparatus according'to claim 3 in which the first, second and thirdroller surfaces are rotatable on the mounting about a common axis.

5. A method of producing at an edge of a metal member of circular crosssection, a zone of greater thickness than the body of the member,comprising the steps of:

a. locally heating successive parts about the circumference of said edgeto a temperature at which said parts can be plastically deformed, bycausing relative movement between a source of heat and the edge of saidmember,

b. deforming the metal at said edge solely by applying applying arestraining force in a direction normal to said deformation force insaid direction of thickening by means of further surfaces which makerolling engagement with said member so as to locate the thickened metalrelative to the remainder of the member, the deformation of the metalbeing progressive starting at the edge of said member.

1. A method of producing at one end of the wall of a thin-walled metalmember of circular cross section, a zone of greater thickness than thewall of the member, comprising the steps of: a. locally heatingsuccessive parts of the circumference of the end of the member to atemperature at which they can be plastically deformed, by causingrelative movement between a source of heat and the circumference of themember, b. deforming the metal solely by applying axial force to thatpart of the circumference of the end of the member which at any instantis heated, by means of a first surface which makes rolling engagementwith the member and moves relatively to the member around thecircumference of the member, and c. applying radial restraint by meansof further surfaces which make rolling engagement with the member so asto locate the thickened metal relatively to the remainder of the member,the first surface at its instantaneous place of contact with the memberbeing always tangent to a plane perpendicular to the axis of the member,and the deformation of the metal being progressive, starting at the endof the member.
 2. A method according to claim 1, including the furtherstep of progressively increasing the spacing between said furthersurfaces during said deforming of the metal.
 3. Apparatus for producingat one end of the wall of a thin-walled metal member of circular crosssection, a zone of greater thickness than the wall of the member,comprising a support for the member and a mounting, means for relativelyrotating the support and the mounting about an axis, a first rollersurface carried by the mounting and adapted to apply axial force to themember, means for relatively moving this first roller surface towardsthe support, a second roller surface and a third roller surface bothcarried by the mounting and adapted to engage the inner and the outerfaces of the zone respectively at a common station, means for shiftingthe second and third roller surfaces relatively to each other in adirection perpendicular to the axis of relative rotation of the supportand the mounting, and means on the mounting adjacent to the first rollerfor locally heating the end of the wall of the member.
 4. Apparatusaccording to claim 3 in which the first, second and third rollersurfaces are rotatable on the mounting about a common axis.
 5. A methodof producing at an edge of a metal member of circular cross section, azone of greater thickness than the body of the member, comprising thesteps of: a. locally heating successive parts about the circumference ofsaid edge to a temperature at which said parts can be plasticallydeformed, by causing relative movement between a source of heat and theedge of said member, b. deforming the metal at said edge solely byapplying a deformation force perpendicular to said edge and normal tothe direction in which said thikening is to be effected at that part ofthe circumference of said edge which at any instant is heated, by meansof a first surface whiCh makes rolling engagement with the edge of saidmember and moves relative to said edge around the circumference thereof,and c. applying a restraining force in a direction normal to saiddeformation force in said direction of thickening by means of furthersurfaces which make rolling engagement with said member so as to locatethe thickened metal relative to the remainder of the member, thedeformation of the metal being progressive starting at the edge of saidmember.